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Journal : Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)

Tricopter Vehicle Frame Structure Design Integrated as Platform of Fixed Wing Atha Mapper 2150 Kaspul Anuar; Warman Fatra; Musthafa Akbar
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 64 No 2 (2020): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (412.545 KB) | DOI: 10.36842/jomase.v64i2.218

Abstract

To upgrade aerial vehicle of Atha Mapper 2150 capable of vertical take-off and landing capability, it needs to be integrated to the tricopter vehicle. In this study the tricopter frame structure was designed based on the Atha Mapper 2150 fixed wing vehicle. This study began with a calculation process to determine the dimensions of the tricopter.. Next, the process of building four tricopter concept designs with variations of the shape of the frame and the cross section of the arm. The four concept designs are selected using a decision matrix. Based on the values in decision matrix table, the design concept I (Y configuration and rectangular arm cross section) was the best design, because it has the highest weighting value. The selected design was then simulated for its structural strength in Ansys software by giving a load of thrust to the three arms of the tricopter frame. In the middle of frame is given a boundary condition in the form of hinges. From the static simulation results of the tricopter frame structure, the maximum stress value was 54,126 MPa, which occurred on the M3 arm. The greatest total deformation also occurred in the M3 arm with a value of 10,335 mm. The safety factor value of tricopter frame structure was 8.77. This shows the tricopter frame structure with the main material in the form of carbon fiber, acrylic and PLA meets the required safety criteria.
Failure Assessment Diagram Constraint Used for Integrity Analysis of Cylindrical Shell with Crack Akbar, Musthafa; Setiawan, Rachman
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 27 No 1 (2016): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36842/jomase.v27i1.427

Abstract

During itsoperation time, cylindrical pressure vessel could experience cracks. If this happens, the question is raised whether the pressure vessel could still be used or not, moreoever whether further treatment is required. In process and petroleum industry, an integrity analysis using Fitness For Service methodology is common, for instance referring to API 579/ASME FFS-1 2007 Code. Level 3 assessment within the Code requires a finite element simulation in order to generate both the evaluation point and the Failure Assessment Diagram (FAD) that serves as an acceptance criteria. Here, a parametric study based on the methodology given by the Code has been carried out to generate such result for the cases of internal longitudinal crack defect in a cylindrical shells for a number of common cases, in terms of thickness-to-radius ratio, crack size ratio, and crack aspect ratio. The evaluation of Stress Intensity Factor is determined through J-integral parameter found using a finite element analysis with a specially-meshed strategy incorporating the crack. The result of the model is first verified with that of the Code for a number of cases, before being used for parametric study. The model yields a relatively close comparison with that of the Code. A number of regressed equation was derived for several cases, and proposed to be used in integrity assessment of cylindrical shell. A procedure of using the parametric study result from this investigation is also outlined here.
Integrity Assessment of Cracked Pressure Vessel with Considering Effect of Residual Stress Based on Failure Assessment Diagram Criteria Akbar, Musthafa; Setiawan, Rachman
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 28 No 1 (2016): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36842/jomase.v28i1.422

Abstract

During the period of its operation, a pressure vessel may experience excessive loading which can cause crack defects. Integrity analysis needs to be carried out to evaluate the feasibility operation of that cylindrical pressure vessel with defects. In this paper, integrity assessment of cracked pressure vessel under internal pressure and tensile residual stress was conducted based on failure assessment diagram criteria. This criteria applied widely and adopted in API 579-1/ASME FFS-1 2007 Code. There are three assessment levels provided in code. Level 1 and 2 assessment performed using analytical calculation while Level 3 assessment is conducted using finite element method. On a case study, failure criteria for the integrity analysis is based on the Failure Assessment Diagram (FAD), that distinguish safe and unsafe region based on two failure criteria, namely brittle fracture and ductile fracture. This diagram is built using finite element method with the assumptions of both Linear Elastic Fracture Mechanics (LEFM) and Elastic Plastic Fracture Mechanics (EPFM). Based on Level 1 assessment, the pressure vessel under study is not recommended to be operated, whilst based on Level 2 and 3 assessments the pressure vessel is considered acceptable. This study concludes that Level 1 and 2 analysis provide more conservative results when compared with level 3 analysis. Failure Assessment Diagram for Level 3 analysis relatively more conservative at elastic-plastic region (0.4<Lr<1), but less conservative at plastic collapse region. Parametric studies performed with increasing operating pressure and size of defects. Based on analysis, failures of the pressure vessel occur at pressure of 403 psi and an aspect ratio of 0.18 for analysis with including the effect of tensile residual stresses. Meanwhile, if the analysis is done by ignoring the effect of residual stress, pressure vessel failed at pressure of 589 psi and leak when aspect ratio reaching 0.42.
Finite Element Analysis of Wood Structural Joints on Traditional Wooden Ship , Yohanes; Akbar, Musthafa; Aksa, Reysca Admi
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 30 No 1 (2016): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36842/jomase.v30i1.416

Abstract

Traditional ship often made by woods materials and it was made without proper engineering procedure. This research focuses on a case study in BaganSiapiapi, Riau Province, Indonesia where a large wooden ship was manufactured. One of the sources of material failure in the manufacturing of wooden ship is located at the joint. In this research, a modification of joint design has been studied where 4 design model have been offered by using glue as the attachment materials and 5 other design by using bolt as the connection method. A finite element method was used to study the strength of the joint which has been guided by a standard issued by Indonesian Classification Bureau. There are 9 design of joints were modeled and studied which have been varied using two different wooden materials such as ‘keruing’ and ‘meranti’. A uniform loading was applied on all models and materials. The applied loadings are buoyancy force, gravity force, and pre-stress loading at the bolt. The result from simulation generates a stress-contour indicating the stress level on the materials. It was concluded that the model of connection hooked straight lip which is connected with 4 pieces M14 bolts with wood material keruing a recommended model for traditional wooden boat building. This design gives 1.605 mm deformation with maximum stress of 217.51 MPa.
Failure Prediction of Cracked Pressure Vessel under Fatigue Load Based on API 579 Standard and Finite Element Method Akbar, Musthafa
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 37 No 1 (2016): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36842/jomase.v37i1.397

Abstract

Failure prediction of cracked pressure vessel is analyzed based on crack growth behavior under fatigue loading. The major objective of this study was to investigate and validate the use of commonly used industry standard with finite element method in order to predict failure of cracked pressure vessel. Growing of crack due to fatigue load was analyzed using both analytical and finite element method. In analytical side, API 579 Code is used with involving safety and correction factor which will increase conservatism degree of the results. Pressure vessel with D/t ratio 40, 60, and 80 were taken into analysis. Semi elliptical cracks in longitudinal and circumferential position were included into analysis with ratio a/t=0.3, 0.5, 0.8 and a/c=0.15, 0.125, 0.1. In this paper, there are 84 numerical model were solved numerically and plotted into several curves. Comparisons between API 579 and finite element simulation show that pressure vessel with D/t=40, 60 and 80 have percent error about 2.16 %, 9.32 % and 10.57 %, respectively. This results are reasonable due to several safety factor are included in API 579 analysis. Results of this paper can be used as consideration for make a decision regarding to integrity analysis of pressure vessel.
Structural Analysis of Pylon Head for Cable Stayed Bridge Using Non-Linear Finite Element Method Akbar, Musthafa; Nugraha, Aditya Sukma
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 51 No 1 (2018): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (770.994 KB) | DOI: 10.36842/jomase.v51i1.40

Abstract

Cable-stayed bridge is a type of bridge structure that commonly used for long-span range. This study provides an important opportunity to advance the understanding nonlinearities of material and geometry which is used for pylon of cable-stayed bridge structure. This study limited to response of pylon structure subjected to tension load which already calculated previously using structural analysis program. The methodology of structural analysis in order to determine working stress in the pylon structure under cable tension load is based on non-linear finite element method by incorporating an elastic-plastic material model and involve large deformation logarithm. In this study, laboratory experiment was held using test method ASTM A370. In finite element of plasticity analysis Ramberg-Osgood model was used to generate stress-strain curve of material. Based on finite element analysis that we have done, both of pylon structure will be fail or experience permanent plastic deformation if it subjected to loading conditions as mentioned in this research. The most critical regions in the structure are at Section A2 for left side pylon and at Section A11 for right side pylon. In critical regions, maximum Von-Misses stress reach 427.96 MPa for left side pylon and 430.56 MPa for right side pylon. Those stress value are beyond yield strength of material which is used for the structure. Design optimization can be done for the structure with some considerations, e.g. modification of design in the critical region, improve material properties or just change thickness of material in the critical regions.
The Performance of Undershot Water Turbine Combined With Spiral Tube Pump On Empowerment of Energy Resources Local Contiguous Small River Asral, Asral; Akbar, Musthafa; Syafri, Syafri
Journal of Ocean, Mechanical and Aerospace -science and engineering- Vol 42 No 1 (2017): Journal of Ocean, Mechanical and Aerospace -science and engineering- (JOMAse)
Publisher : International Society of Ocean, Mechanical and Aerospace -scientists and engineers- (ISOMAse)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1368.747 KB) | DOI: 10.36842/jomase.v42i1.186

Abstract

Hundreds of kilometers of irrigation canals are generally contiguous the village has not been maximally helpful as well most of damaged. Basically, in the water flow available an amount of energy could be harnessed as a renewable energy resources. Shortage of water and electricity supplies are the major issues encountered by the villager. Irrigation canals have head differences including low coupled lies in lowland areas. Picohydro electric generation, undershot-type water turbine suited for low high head applications in attemp to gain the electricity. To move the water, spiral tube pump mounted on the turbine can be installed simultaneously on generating systems. The turbine developed has an outer diameter of 2 m with 18 pieces of straight blade prepared from the material of aluminum. On the side of the turbine wall embeded the spiral tube pump with 5 coils was designed to operate concurrently with electrical generation. The height of water resources varied by controlling the opening of sluice gates to find out the potential. Throughout study the maximum electric voltage achievements was 125 volt. At the same time, the pump discharged the water with 9 liters per menit. These results provide sufficient supply of freshwater and electrical power for a family at contiguous area.